These 5 mysterious underground cities were built thousands of years ago — without modern tools, yet with incredible ...

It is the largest excavated underground city in the world and stretches more than 85 metres below the surface.

Contractors renovating a historic home in Belgium stumbled upon the entrance to a secret tunnel identified by archaeologists ...

Researchers explore the possibility of a secret passage that may have been used in ancient times for strategic, diplomatic, or commercial purposes.

Throughout the arid regions of Iran, agricultural and permanent settlements are supported by the ancient qanat system of tapping alluvial aquifers at the heads of valleys and conducting the water ...

A heated debate has erupted among Egyptologists after researchers claimed to have found an “underground city” beneath the Pyramids of Giza. Is the discovery, based on radar images, groundbreaking or ...

Calcium carbonate dust found in the tunnels is also a common excretion from microbes that live in these types of rocks. However, no fossilized organisms have yet been found—just evidence of ...

The giant tunnels of the Metropolitan Area Outer Outer Underground Discharge Channel. Credit: Dddeco / Wikimedia Commons The region where this drainage system is located has historically been prone to ...